The third-gen Toyota 4Runner (1996–2002) is a certified legend in the off-road world — and for good reason. But if you have driven one with tired factory control arms and blown-out bushings, you know the rear end can feel loose, noisy, and imprecise. In this guide, Spence from Core 4x4 walks through the full rear suspension upgrade on a 1999 4Runner using the Camp Series K5 kit, which includes rear control arms and a track bar (panhard rod).
Whether you are running a leveling kit, a mild lift, or even factory ride height, replacing worn-out rear control arms is one of the most impactful upgrades you can make. This video is also Core 4x4’s first Toyota build on YouTube — and it went surprisingly well (mostly).
Fitment: Toyota 4Runner 1996–2002 (3rd Generation). Core 4x4 also makes parts for the 4th-gen 4Runner, FJ Cruiser, and Tacoma (coming soon).
What’s in the Camp Series K5 Kit?
The K5 designation means five pieces: four rear control arms (two uppers and two lowers) plus one rear track bar (panhard rod). This kit addresses the entire rear suspension geometry in one shot.
Core 4x4 offers three tiers for their Toyota parts, just like their Jeep and Dodge lines:
| Series | Tubing | Joints | Adjustability | Best For |
|---|---|---|---|---|
| Cruise | Standard wall | Bushings on both ends | Single adjustable | Daily driving, light trail use |
| Camp | 5/16” wall DOM | Bushing + Johnny Joint | Single adjustable | Daily-driven trail rigs (this install) |
| Crawl | 5/16” wall DOM | Johnny Joints on both ends | Double adjustable (left & right threaded) | Dedicated off-road builds |
The Camp Series sits in the sweet spot for most 4Runner owners. You get heavy 5/16-inch wall DOM tubing, a Johnny Joint on the adjustable end for maximum articulation, and a quiet poly bushing on the other. For a daily-driven 4Runner with a leveling kit, the Camp Series is the play.
Vehicle Prep: Penetrating Fluid Is Your Best Friend
Before touching a single bolt, Spence sprayed every rear suspension fastener with penetrating fluid and let it sit overnight. On a 1999 4Runner from Utah, rust is a given. Spending an extra day letting PB Blaster do its job can save you hours of fighting seized hardware.
Pro tip: Upgraded hardware is an option when ordering the kit. On a rusty vehicle from a salt state, it is absolutely worth the investment — you do not want to reuse corroded bolts on fresh arms.
Quick Install Overview: Leveling Kit vs. Lifted Setup
The install approach depends entirely on your 4Runner’s setup:
- Leveling kit or factory height: This is the easy scenario. You are not changing arm lengths — just matching the factory measurement. You can do it in your driveway with a floor jack, removing one arm at a time, matching the length, and bolting the new one in.
- Lifted 4Runner: You will need to set arm lengths for your specific lift. Core 4x4 can provide starting measurements, but every vehicle is loaded and weighted differently. The general rule: lower control arms set your wheelbase (centering the wheel in the wheel well), and upper control arms set your pinion angle (for proper driveline geometry).
Either way, the goal is the same: wheel centered in the wheel well and pinion angle correct for your driveline. Core 4x4’s team can help you dial in starting lengths for your specific setup.
How to Measure Your Old Control Arms
When the first factory arm came off this 4Runner, both crush sleeves fell right out — the bushings were completely destroyed. That makes measuring tricky because the big empty holes make it hard to find true center-on-center distance.
Here is the trick Spence uses when the bushing sleeves are the same diameter on both ends:
- Place your tape measure on the outside edge of one sleeve and the inside edge of the opposite sleeve
- That measurement equals center-on-center — you are effectively adding half a diameter on one end and subtracting it on the other, which cancels out
- For this 4Runner, that came out to exactly 21 inches
When matching to the new Camp Series arm (which has a Johnny Joint on one end — a different diameter than the bushing end), the stacking method works better: lay the old arm on top of the new arm, drop your bolts through both, and match them up visually. Then verify with the tape measure.
The physical difference between the factory arm and the Core 4x4 arm is dramatic. The factory arm is roughly an inch and an eighth of thin-wall tubing that you can feel flex in your hands. The Camp Series arm is inch-and-three-quarter, 5/16-inch wall DOM — you are never bending or breaking one of these.
Greasing the Bushings: Do This Before Install
Before bolting the new arms onto the 4Runner, Spence applies a thin layer of grease to the bushing wear surfaces — specifically where the bushing contacts the mounting bracket. This eliminates any initial squeaking and speeds up the break-in process. The poly bushings on the Camp Series are quiet by design, but a little grease upfront makes the first few hundred miles completely noise-free.
The Johnny Joint side does not need grease — those joints are self-lubricating with their own grease fittings.
The Install: What Went Right and What Got Tricky
The good news: on this 4Runner, the lower bolts came out clean. If you have watched Core 4x4’s recent Jeep videos, you know that seized lower bolts have been a recurring nightmare. The Toyota earned some respect here — Spence was pleasantly surprised.
The not-so-good news: when you swap arms on a lift (as opposed to on the ground), the axle shifts. With the factory lower arm removed, the axle dropped and moved to one side because the track bar (panhard rod) was still pulling it. Here is how they solved it:
- Disconnected the track bar to let the axle float freely
- Used a rubber mallet and leverage to nudge the axle into position
- Bolt holes lined up once the track bar was out of the equation
Driveway tip: If you are doing this at home on the ground, remove one arm at a time. With the vehicle’s weight on the suspension, the axle stays put and bolts line up easily. The on-lift method shown in the video requires more maneuvering because the axle hangs at full droop.
The Bolt-Cutting Situation
One bolt had to be cut. The aftermarket shock’s reservoir was blocking the bolt from sliding out. Rather than removing the entire shock, Spence cut the bolt and reinstalled it from the opposite side. Trail-fix energy — but it works perfectly.
A Note on the Factory Arms
When Spence pulled the old arms off, he could see one of them flexing when hit with a hammer. The thin-wall factory tubing is not built for serious use. If your 4Runner still has the original arms and you run any kind of lift, the bushings are almost certainly deteriorated — even if you have not noticed symptoms yet.
The Finished Build
With all four rear control arms and the new track bar installed, this third-gen 4Runner is transformed. The improvements you can expect:
- Better ride quality on-road: Fresh bushings and proper arm geometry eliminate the looseness and wandering that worn factory arms cause
- More articulation off-road: The Johnny Joint on each arm allows significantly more flex than the original rubber bushings
- Zero maintenance worry: The 5/16-inch wall DOM tubing is virtually indestructible in normal (and abnormal) use
- Adjustability: If your setup changes — new lift, different tires, payload changes — you can dial in the arm length to compensate
Tools Required
- Two-post lift or floor jack and jack stands
- Socket set (metric)
- Torque wrench
- Tape measure
- Rubber mallet
- Pry bar / screwdriver for leverage
- Penetrating fluid (PB Blaster or equivalent)
- Grease (for bushing surfaces)
- Reciprocating saw or angle grinder (in case you need to cut a bolt)
Frequently Asked Questions
Shop Toyota 4Runner Control Arms
Fitment: Toyota 4Runner 1996–2002 (3rd Gen). Questions? sales@core4x4.com | support@core4x4.com
